g0201_0300.s0227_basic_calculator_ii

Class Solution

java.lang.Object

g0201_0300.s0227_basic_calculator_ii.Solution

public class Solution
extends Object

227 - Basic Calculator II.

Medium

Given a string s which represents an expression, evaluate this expression and return its value.

The integer division should truncate toward zero.

You may assume that the given expression is always valid. All intermediate results will be in the range of [-231, 231 - 1].

Note: You are not allowed to use any built-in function which evaluates strings as mathematical expressions, such as eval().

Example 1:

Input: s = “3+2*2”

Output: 7

Example 2:

Input: s = “ 3/2 ”

Output: 1

Example 3:

Input: s = “ 3+5 / 2 ”

Output: 5

Constraints:

• 1 <= s.length <= 3 * 105
• s consists of integers and operators ('+', '-', '*', '/') separated by some number of spaces.
• s represents a valid expression.
• All the integers in the expression are non-negative integers in the range [0, 231 - 1].
• The answer is guaranteed to fit in a 32-bit integer.

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	calculate(String s)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

calculate

public int calculate(String s)